Efficacy of first-line tyrosine kinase inhibitors plus immune checkpoint inhibitors in metastatic fumarate hydratase-deficient renal cell carcinoma / 中华泌尿外科杂志

ABSTRACT

Objective:To evaluate the efficacy of first-line tyrosine kinase inhibitors (TKI) plus immune checkpoint inhibitors (ICI) in metastatic fumarate hydratase-deficient renal cell carcinoma (FH-deficient RCC).Methods:The data of 87 metastatic FH-deficient RCC patients from West China Hospital ( n=44), Renji Hospital ( n=27) and Sun Yat-sen University Cancer Center (n=16) from Mar 2019 to Aug 2022 were retrospectively analyzed. The median age was 37(30, 47) years, the male to female ratio was 1.9∶1. The median size of tumor was 7.5(5.0, 10.0) cm. Sixty-one patients (70.1%) had germline FH mutations, and 26 patients (29.9%) had somatic FH mutations. Forty-nine patients (56.3%) metastasis disease at initial diagnosis, and 38 patients (43.7%) had metachronous metastasis. The most common site of metastasis was lymph node (41/87, 47.1%), followed by bone (33/87, 37.9%), liver (22/87, 25.3%), and lung (14/87, 16.1%). Fifteen patients (17.2%) had weak expression of FH protein and 59 patients (67.8%) had positive PD-L1 expression. The most common treatments were sintilimab plus axitinib (52/87, 59.8%), followed by pembrolizumab plus cabozantinib (7/87, 8.0%), tirelizumab plus axitinib (6/87, 6.9%), pembrolizumab plus axitinib (5/87, 5.7%), and toripalimab plus axitinib (4/87, 4.6%). Thirteen patients (13/87, 14.9%) received other ICI plus TKI combination treatments. Statistical analysis was conducted using R 4.2.3 software. Kaplan Meier survival curve was used to evaluate survival data, and log-rank test was used to compare differences between treatment groups. Results:The overall objective response rate (ORR) and disease control rate (DCR) of first-line TKI + ICI were 39.1% and 89.7%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 16.5 months and 71.0 months, respectively. For first-line sintilimab plus axitinib, the ORR and DCR were 44.2% and 92.3%, respectively. The median PFS was 17.3 months and the median OS was not reached for this combination treatment. The efficacy of first-line tirelizumab plus axitinib was inferior to other treatment strategies (median PFS: 4.0 vs. 16.6 months, P<0.001; median OS: 22.0 vs. 71.0 months, P=0.043). Subgroup analyses further showed that the efficacy of ICI+ TKI combination therapy was consistent in patients with different clinicopathologic and genomic features. However, patients with liver metastasis had shorter OS than those without liver metastasis (median OS: 26.3 vs. 71.0 months, P=0.021). Conclusion:First-line TKI + ICI is effective for metastatic FH-deficient RCC and can significantly prolong the survival of the patients.